This invention relates to communication systems, including but not limited to a method for allocating resources in a wide-area communication systems such as radio frequency (RF) communication systems.
Wide-area dispatch communication systems are known. Commercial examples of such systems include SMARTZONE(trademark) and OMNILINK(trademark) systems available from Motorola, Inc. In these systems, multiple base sites are geographically distributed over a wide-area to provide over-the-air communications for communication units (e.g., vehicle-mounted or portable communication units in a land mobile system and communication unit/telephones in a cellular system) travelling in the area. The base sites are connected via a communication path to a zone controller that performs call control and mobility management for communication units and talkgroups in the system. Each site provides one or more communication resources, including RF resources such as narrow band frequency modulated communication resources, time division multiplex slots, frequency pairs, and so forth. A zone manager is operably coupled to the zone controller in the system to configure system parameters, physical device configuration, and communication unit, and talkgroup attributes.
In existing wide-area dispatch systems, communication units are grouped for intercommunication. Talkgroups are groupings of communication units that wish to intercommunicate. For example, the fire department of a municipality uses a talkgroup to facilitate communication between all members of the fire department. Similarly, the police department may use another talkgroup to facilitate communication among the members of the police department. Typically, talkgroups are assigned a system-wide priority such that communications between members of a high-priority talkgroup are allocated resources before communications between members of a low-priority talkgroup. With such allocation, resources needed for a call, such as RF communication resources, are more efficiently allocated. In addition, individual communication units are assigned a system-wide priority. A particular user may be assigned a higher priority than other users without regard to the user""s talkgroup affiliation. For example, a police chief is likely to be assigned a higher priority than a patrol officer, even though the talkgroup for the police department has one talkgroup priority. The individual communication unit priority assignments are used for individual telephone interconnect or private calls. When communication resources are allocated for talkgroup calls, the higher of the talkgroup priority or requesting communication unit priority is used to allocate resources. For private calls (communication unit to communication unit) the higher of the requesting and target priorities is used to allocate resources. For telephone interconnect calls, the priority of the requesting communication unit is used to allocate resources.
Presently, multiple municipalities may share a single wide-area dispatch communication system. This sharing provides communication between, and facilitates cooperation between, users in different municipalities. For example, the police department of Metropolis A may communicate and provide backup to the police department of neighboring Metropolis B by virtue of a shared communication system. In addition, shared resources and administration of the communication system provide cost efficiency.
Although benefits and efficiencies of sharing wide-area dispatch communication systems between multiple governmental bodies and a diversity of users exist, difficulties with such a system may be present. In particular, when there are limited resources, contention for system resources occurs. The existing priority scheme for allocating resources is not sufficient for diversified and shared use of wide-area dispatch communication systems. For example, a police officer who lives in Metropolis A and works in Metropolis B, travels into Metropolis A on his way home from a shift. Metropolis A and Metropolis B share a wide-area communication system. Because the police officer has a relatively high talkgroup priority associated with Metropolis B, where he works, this high priority travels with him to Metropolis A, where he lives, because priorities are typically assigned on a system-wide basis. Although the police officer""s high priority in Metropolis B is quite desirable, the officer""s relatively high priority in Metropolis A may not be so desirable.
One known solution for allocating resources based on the geographical location of the communication unit is to segment the communication system. Segmentation prevents a user from utilizing a site in a particular geographical region. This solution does allocate resources geographically, but isolates some users in certain geographical locations, which isolation may be detrimental. A similar solution allocates select resources at a site for particular communication units or talkgroups. For example, the police officer in the example above is allowed to use only certain communication resources in Metropolis A, with the other communication resources are dedicated for use by persons working in Metropolis A. This solution reduces the total number of communication resources available to Metropolis A and generally requires more communication resources at every site. These solutions are not adequate for efficiently providing a priority for users based on the geographical location of the user.
Accordingly, a need exists for a method of allocating resources to communication units in a communication system based on the geographical location of the communication unit.